"This book is an introduction to a line of thinking about the macro economy that stands in bold opposition to much of the macroeconomic literature not only of the last 25 years, but of much of the work of 25 years before that- the work that led to the microfoundations work. The approach to macro presented in this volume significantly differs from much of both Classical and Keynesian thought- whether prefixed by new, neo, or whatever. Thus, it is in opposition not only to the New Classical and New Keynesian macroeconomics of the last 15 years, but also to the NeoKeynesian and neoclassical macroeconomics of the last 50 years.
Given such strong claims it is only natural that one wonders how, after 50 years of development, can there be such a fundamentally different approach to macro? I can best answer that with an analogy. Say you are at the base of two mountains whose peaks are above the clouds. You want to climb to the higher peak which means that you must choose one of the two. You do; you choose Mountain A- the Walrasian mountain; you start working your way up the slopes further and further, until finally you get above the clouds. When you do, you see that Mountain B- let's call it a Post Walrasian mountain- is the far higher one. That's what we believe happened in macroeconomics.
This analogy should help explain why a dramatic new approach may be needed to further our understanding of macro issues and why a discussion of that new approach involves the foundations of economic analysis, not extensions of existing work. Whereas most of the debate in macro over the last 50 years has concerned whether we should follow this path or that path, the papers in this volume will be arguing that the paths aren't the problem; the problem is the mountain- the core Walrasian foundation of macro theory."